Abstract: Mixing Zone Diagenesis Within an Inland Blue Hole 

AAPG Bulletin ◽  
1999 ◽  
Vol 83 (1999) ◽  
Author(s):  
HICKEY, T. DONALD, and EUGENE A. SH
Keyword(s):  
1999 ◽  
Vol 39 (4) ◽  
pp. 185-192 ◽  
Author(s):  
A. M. J. Ragas ◽  
R. S. E. W. Leuven

Water authorities apply a diversity of models and input data to set water quality-based emission limits in discharge permits. To illustrate the consequences of model and data selection, two complete mixing models and four mixing zone models used in Germany, the United Kingdom (UK), the Netherlands and the United States of America (USA) were selected and applied to various discharges of cadmium. The maximum allowable annual cadmium load was calculated for each model and diverging input data for upstream flow, upstream concentration, effluent flow and effluent concentration. Due to model selection, differences in pollutant loads amounted to a factor 3. Harmonisation of the derivation of water quality-based emission limits is necessary to prevent widely divergent pollutant loads under comparable environmental conditions.


2016 ◽  
Author(s):  
James Kerr ◽  
◽  
Lisa E. Park Boush ◽  
Dana Michelle Yakabowskas ◽  
Amy Myrbo
Keyword(s):  

2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Yannick Bury ◽  
Pierre Graumer ◽  
Stéphane Jamme ◽  
Jérôme Griffond

Author(s):  
Robert L. Doneker ◽  
Gerhard H. Jirka
Keyword(s):  

2013 ◽  
Vol 15 (4) ◽  
pp. 1474-1490 ◽  
Author(s):  
Ata Allah Nadiri ◽  
Elham Fijani ◽  
Frank T.-C. Tsai ◽  
Asghar Asghari Moghaddam

The study introduces a supervised committee machine with artificial intelligence (SCMAI) method to predict fluoride in ground water of Maku, Iran. Ground water is the main source of drinking water for the area. Management of fluoride anomaly needs better prediction of fluoride concentration. However, the complex hydrogeological characteristics cause difficulties to accurately predict fluoride concentration in basaltic formation, non-basaltic formation, and mixing zone. SCMAI predicts fluoride by a nonlinear combination of individual AI models through an artificial intelligent system. Factor analysis is used to identify effective fluoride-correlated hydrochemical parameters as input to AI models. Four AI models, Sugeno fuzzy logic, Mamdani fuzzy logic, artificial neural network (ANN), and neuro-fuzzy are employed to predict fluoride concentration. The results show that all of these models have similar fitting to the fluoride data in the Maku area, and do not predict well for samples in the mixing zone. The SCMAI employs an ANN model to re-predict the fluoride concentration based on the four AI model predictions. The result shows improvement to the CMAI method, a committee machine with the linear combination of AI model predictions. The results also show significant fitting improvement to individual AI models, especially for fluoride prediction in the mixing zone.


2012 ◽  
Vol 150 (3) ◽  
pp. 385-395 ◽  
Author(s):  
ALICJA M. LACINSKA ◽  
MICHAEL T. STYLES

AbstractMineralogical studies of a silicified serpentinite from the United Arab Emirates throw light on the formative processes. The silicified serpentinite is a residuum of a palaeo-weathering surface that probably developed in a temperate climate with alternating wet and dry periods during middle Eocene to late Miocene times. The rock textures indicate that silicification occurred in a fluid-saturated zone. Silica precipitation is favoured at near-neutral pH. In this study we infer that these pH conditions of the mineralizing fluids could arise in a near-surface mixing zone where acidic meteoric and hyperalkaline groundwater fluids are mingled. This mingling is believed to have resulted from alternating processes of evaporation and precipitation that prevailed during dry and wet seasons, respectively. The silicified serpentinite is composed of > 95% quartz and exhibits a ghost texture of the protolith serpentinite. Preservation of the textures indicates an iso-volumetric grain-by-grain replacement by dissolution of Mg-silicate and simultaneous precipitation of either opal or microquartz as siliceous seeds. These were subsequently overgrown by silica that was probably remobilized from deeply weathered regolith elsewhere.


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